Possible Clues:

• The player seated on the left side of a large piano stool
• In time ordered to start section of duet
• What will make son soon participant in piano duet?
• Two functions restricting leg's lower part
• Lower part of a 10-Down duet
• Lower part of a duet
• Musical part put back on top of organ
• Part played by duettist performing during dry party
• Contralto's last bit is the lower part of two
• Musical part that oboe has, but not violin